In the bearing technology it is known that bearings are provided so that an electrical current can pass through the bearing elements. If this is allowed with no specific provisions there is the danger that sparks are created between the bearing rings and the rolling elements due to the transfer of the current. Detrimentally, the sparks create craters on the rolling elements and bearing ring raceways which lead to bearing failure.
To avoid the creation of sparks different measures are known. One possibility is to insulate the bearing rings, e.g. with a cover of ceramic material. By doing so no current transfer can occur through the bearing. Also electrical non-conductive rolling elements can be employed, specifically made of a ceramic material. Both mentioned measures are quite cost intensive. Also the use of an electrically conductive grease for lubrication can be taken into account. This approach is not always fully satisfactory.
Also, special coal brushes are known to establish electrical conductivity between the bearing rings. But also this approach is quite cost intensive. Also, for doing so sufficient mounting space is required which is not available in all cases.
Thus, it is an object of the present invention to develop a sealing arrangement of the generic kind which prevents the current flow between the bearing rings and the rolling elements in an effective manner and in a cost-efficient way. That is, an electrical conductivity should be established between the two machine elements in an effective and economical manner.